Fatal error: Uncaught Error: Interface "BookStack\Activity\Notifications\Handlers\NotificationHandler" not found in C:\WebServer\htdocs\bookshelf\app\Activity\Notifications\Handlers\BaseNotificationHandler.php:13 Stack trace: #0 {main} thrown in C:\WebServer\htdocs\bookshelf\app\Activity\Notifications\Handlers\BaseNotificationHandler.php on line 13